Moreover, Gandhi faces credible complaints that his office is much friendlier about lowering tax bills for big commercial developers than about helping elderly, low-income residents who are struggling to keep their homes.

Unfortunately, Gandhi’s agency often turns defensive and uncommunicative when criticized. This self-defeating reflex has been highlighted by the revelation (by this newspaper) that the agency sought to avoid publicizing internal audits describing various shortcomings.

The persistent ailments and inadequate response have eroded the credibility and reputation of one of the District’s most important agencies. Even council member Jack Evans (D-Ward 2), who is one of Gandhi’s strongest supporters, admonished him at the hearing.

“There’s a series of drip, drip, drip that appear to be management problems,” Evans said. “It’s too damaging to your office to have this same drumbeat every six months. This time, you have to take [the] suggestions seriously.”

Perhaps the pressure will finally make a difference. But the record isn’t promising.

Of course you recall Harriette Walters’s whopping $48 million embezzlement from the District’s tax office, which Gandhi oversees. After it came to light in 2007, everyone involved went to great lengths to assure the public that reforms were instituted so that it would never happen again.

Then, a year ago, a former tax examiner was caught stealing more than $400,000. The loss wasn’t nearly as big, but it was still worrisome.

Now we learn from an internal audit drafted in March that procedures for changing tax assessments had multiple problems.

The staff was unable to locate about 18 percent of documents requested by the auditors. Between a third and a half of the cases in a sample were missing some paperwork. One in seven had math errors.

Gandhi’s response was that more reforms were being implemented. It’s unsettling, however, that top Gandhi deputies apparently tried to keep the audit from becoming public this past spring, just as Mayor Vincent Gray (D) was weighing whether to appoint Gandhi to a new five-year term. (He did.)

The council hearing also highlighted an eye-opening divergence in attitudes toward Gandhi between commercial property interests and individual homeowners.

Witnesses representing big-building owners praised Gandhi’s office for speeding up the pace of settlements in tax- assessment disputes. They said the deals have pared a sizable backlog. Needless to say, most of those settlements resulted in a lowering of taxes from the original assessment.

By contrast, individual homeowners’ representatives complained of long-standing problems with inaccurate assessments and difficulties getting adequate responses from the city in tax disputes. Elderly residents on fixed incomes are at especially high risk of losing their homes in forced sales to pay taxes.

“We get a lot of feedback from our clients that the OTR [Office of Tax and Revenue] is difficult to work with. There’s not really any accountability in terms of front-desk staff,” said Amy Mix, a supervising attorney with the AARP Legal Counsel for the Elderly.

Gandhi has survived in his job since 2000 largely out of respect for his unquestioned role as a principal architect of the District’s financial renaissance after the control board era of the late 1990s. Anybody who suggested replacing Gandhi was instantly warned that Wall Street wouldn’t tolerate it, because he’s the guy the bond traders trust.

That might have been the case in 2007, when the Walters scandal erupted. Five years later, however, he’s not indispensable.

One of the District’s top advisers in the New York financial community said that Wall Street wouldn’t like losing Gandhi but that it wouldn’t “freak out” if he departed. That’s because Gandhi has built a legacy of safeguards to protect the city’s finances.

“It would not help if Dr. Gandhi left. Would it cause a calamity? No, because he’s put in place a lot of institutional procedures, which should carry on for at least several years,” said William Cobbs, chairman of the Public Resources Advisory Group.

Gandhi’s latest problems aren’t so severe as to justify trying to force him out. But he needs to do as well fixing his agency’s administrative challenges as he did rescuing the District’s credit rating. And he should make sure that his agency responds as well to retired homeowners living on Social Security as to building owners worth millions.

For previous Robert McCartney columns, go to washingtonpost.com/mccartney.